Assume that y varies directly with x, then solve if y=12 when x=15, find x when y=21

and can someone explain to me how they got the answer because i got 16.8

When the Thompson's have their first child, Will, they decide to begin a college savings account for him by depositing $350.00 into an interest-bearing savings account. Will's account is continuously compounded at a fixed rate of 3.4%.

3w - 4z = 8 what is w

Is 3/8 bigger then 1/2

Witch type of angle has a measure of 160 degrees?

Each baby dinosaur made 15 paintings and each adult dinosaur made 7 paintings. The entire herd made 208 paintings in total, and there were 3 times as many baby dinosaurs as adult dinosaurs.

Patrick is doing a card trick using a standard 52-card deck with four suits: hearts, diamonds, spades, and clubs. He shows his friend a card, replaces it, and then shows his friend another card.

The temperature dropped 13 degrees in in 7 hours. the final temperature was - 2 degrees. what was the starting temperature?

What expression is equivalent to 18c^8 d^9/9c^3 d^6

How do I find the missing numbers in this problem - 7 * _ 8 r3

The height of a ball is modeled by f (x) = - 16x^2 + 128x, where x is the number of seconds after the ball is hit. How long is the ball in the air?